Structures of compounds suitable for the attachment of the lipophilic head groups to the PA chains. Reagents and conditions: (i) HOSu/DCC, DMF, 0 °C, 30 min then 25 °C, 2 h, followed by addition of H2N(CH2)3OH, 25 °C, 10 min, 80%; (ii) HOSu/DCC, THF, 0 °C, 30 min then 25 °C, 2 h, 87%.